Dual-Eccentric Linear Motion Mechanism Stable at Dead Points

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Solution Overview

Problem

Dual eccentric arc swinging mechanisms used as driving mechanisms face instability at dead points, leading to unpredictable motion direction changes, which can cause the moving body to stop instead of converting rotating motion into linear motion efficiently.

Innovation Solution

A driving apparatus with a dual eccentric swinging linear motion mechanism, comprising a housing, a rotatable outer shaft, an eccentric inner shaft, and pivot pins that guide linear motion along orthogonal axes, ensuring consistent directionality and stability by using counterweights and guide bodies to overcome dead points.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a dual eccentric arc swinging mechanism is used to convert rotating motion into linear motion, then the conversion function is achieved, but the mechanism becomes unstable at dead points causing unpredictable motion direction

Engineering Contradiction:
Improvestability at dead pointsVSAvoidpredictable motion direction
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

A guide body is introduced as an intermediary component to constrain the moving body. The guide body includes a guide surface that contacts the moving body and guides its motion, preventing the moving body from deviating at dead points. This intermediary structure ensures stable and predictable linear motion conversion without the instability inherent in the dual eccentric arc mechanism alone.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Productivity

If the dual eccentric arc swinging mechanism is used, then rotating motion conversion is achieved, but the moving body may stop at upper and lower dead points instead of continuing linear motion

Engineering Contradiction:
Improvecontinuous linear motionVSAvoidmotion continuity
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The guide body acts as a mediator that maintains continuous motion by preventing the moving body from stopping at dead points. The guide surface provides continuous contact and directional guidance, ensuring the moving body passes through dead points smoothly without interruption, thereby maintaining productivity and motion continuity.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Reliability

If guide bodies are added to constrain moving body motion, then stability and continuous motion are improved, but the device complexity increases

Engineering Contradiction:
Improvemotion stabilityVSAvoidstructure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The guide body is designed with a guide surface that provides constraint only where needed - specifically at the dead points and along the linear path of the moving body. This localized quality approach ensures stability and continuous motion only in the critical areas without unnecessarily complicating the entire mechanism. The guide surface is positioned to contact the moving body at specific locations, providing minimal necessary constraint.

Inventive Principle:
Principle #3Local quality

Data Source

PatentEP3495609B1Driving apparatus provided with swinging linear motion mechanism
Publication Date: 2023.12.27 Z MECHANISM TECH INST
  • EP3495609B1 patent drawingFigure 1
  • EP3495609B1 patent drawingFigure 2
  • EP3495609B1 patent drawingFigure 3

AI summary

According to an embodiment, a driving apparatus includes a housing 12, a first driving body supported in the housing to be rotatable around a first central axis, an eccentric driving body provided in the first driving body to be rotatable around a second central axis parallel to the first central axis, a first pivot provided at one axial end of the eccentric driving body and eccentrically to the second central axis and extending parallel to the second central axis, a second pivot provided at another axial end of the eccentric driving body and eccentrically to the second central axis and extending parallel to the second central axis, a first moving body rotatably coupled to the first pivot and linearly movable along a third central axis orthogonal to the first central axis, a first guide body which guides movement of the first moving body along the third central axis, and a second guide body which guides the second pivot to be linearly movable in a first direction orthogonal to the first central axis.